Viral infection in the renal transplant recipient

Combined Metagenomic Viral Detection and Donor-Derived Cell-Free DNA Quantification in Plasma From Kidney Transplant Recipients

BACKGROUND

Kidney transplant recipients require potent immunosuppression and are predisposed to opportunistic infections, many of which have a viral etiology. Currently, viral assays detect and quantify single pathogens using PCR or qPCR. An unbiased sequencing method with comparable accuracy would allow simultaneous monitoring of multiple viral pathogens and nonpathogenic Anelloviridae. The quantification of donor-derived cell-free DNA (dd-cfDNA) is an established method for the detection of allograft rejection, and a single workflow combining dd-cfDNA quantification and viral detection represents an opportunity to improve patient monitoring and management.

METHODS

Whole genome sequencing of cell-free DNA was performed using 1,980 plasma samples from 256 subjects enrolled in a multi-center study. Non-human sequences underwent reference-assisted assembly and taxonomic annotation of the viral DNA pathogens.

RESULTS

Of the 1,980 samples tested, 1,453 (73.4%) had ≥1 viral detection(s), either a known viral pathogen or torque teno virus (TTV), with positivity rates generally declining 12-18 months post-transplant. Concordance of metagenomic NGS (mNGS) viral detection with qPCR detection was 97.7% (94.1% sensitivity, 98.2% specificity), and a linear relationship was demonstrated between mNGS viral quantitation and qPCR results. BK virus, cytomegalovirus, and Epstein-Barr virus were detected by sequencing up to 60 days prior to independently established clinical diagnoses.

CONCLUSIONS

Whole-genome sequencing allows simultaneous quantification of dd-cfDNA as well as sensitive and early detection of viral infection through secondary analysis of the same sequencing results. In combination with dd-cfDNA, mNGS viral detection may provide additional pathogen surveillance results and serve as a useful biomarker for both over- and under-immunosuppression.

Cytomegalovirus-Associated Colitis as a Cause of Lower Gastrointestinal Bleeding in Kidney Transplant Recipients: A Single-Centered Study

Introduction Cytomegalovirus (CMV) is the most common viral pathogen affecting patients undergoing solid organ transplantation. It is often the most important infection for patients who have undergone kidney transplantation. Clinical presentations of cytomegalovirus infection range from asymptomatic infection to organ-specific involvement. This study aimed to determine the frequency of cytomegalovirus-associated colitis in kidney transplant recipients (KTRs) presenting with lower gastrointestinal bleeding. Methods After the approval of the ethical review committee of the Sindh Institute of Urology and Transplantation (ERC-SIUT), this cross-sectional study was conducted at the Department of Hepatogastroenterology at the Sindh Institute of Urology and Transplantation from January 2021 to December 2021. All the KTRs (six months after the transplantation) of either gender and aged between 18 and 65 years, presenting with lower gastrointestinal (GI) bleeding as per the operational definition, were enrolled in the study. Those patients who were either unfit for the endoscopy or refused to give consent were excluded from the study. Colonic biopsies were reviewed by a consultant histopathologist for the features of CMV infection. Results A total of 95 renal transplant recipients of either gender or age above 18 to 65 years with lower GI bleeding were included in the study. Among them, 84 (88.4%) were males, while 11 (11.6%) were females. The mean age of the patients included in the study was 37±11 years. The most common presenting complaint was fresh bleeding per rectum, which was observed in 73 (76.8%). The most common findings observed on colonoscopy in KTRs with bleeding per rectum were colonic ulcers and erosions noted in 41 (43.1%) and 36 (37.3%) patients, respectively. On histopathology, CMV colitis was noted in 21 (22.1%) patients. On comparison of different baseline variables, the presence of fresh bleeding per rectum and the presence of both ulcers and erosions on colonoscopy were the factors significantly associated with CMV colitis in KTRs. Conclusion CMV colitis is a prevalent condition in KTRs, presenting with lower GI bleeding. Despite the significant occurrence, the levels of CMV viremia were not associated with CMV colitis, suggesting that diagnosis should rely on histopathological confirmation. Prophylaxis during periods of high immunosuppression is crucial to reducing the incidence of CMV infections and improving both graft function and patient survival.

Varicella zoster virus and cytomegalovirus coinfection in a live related kidney transplant recipient: A case report

Key Clinical Message

The immunomodulatory effect of CMV makes coinfection with other microbes, like VZV possible and potentially deadlier in the post kidney transplant period. Treatment should be started promptly. Both infections can be treated with Valganciclovir.

Abstract

Infections are common complications in kidney transplant recipients owing to the lifelong immunosuppression. Cytomegalovirus (CMV) and Varicella Zoster Virus (VZV) infections are quite common in the posttransplant period. Coinfection with both however has been reported only once. The immunomodulatory effect of CMV makes their interaction with other organisms like VZV potentially sinister. This is a case of a young woman who developed coinfection with HZV and CMV in the first month following a live related kidney transplantation from her mother. Transplant surgery went well with good urine output, but serum creatinine did not fall below 1.7 mg/dL. Immunosuppression consisted of intravenous (IV), followed by oral prednisolone, Mycophenolate Sodium (MPS) and Tacrolimus. 25 days after an uneventful surgery, she developed fever, followed by pain and vesicular eruption on the forehead, typical of VZV infection, along with rising creatinine. CMV PCR yielded 300 copies/mL of DNA, which was undetectable in both donor and recipient pre-transplant. Total white blood cell count fell to 2 × 109/L. MPS was temporarily stopped. Treatment with Valgancyclovir led to resolution of fever, skin lesions and brought serum creatinine down to baseline over 2 weeks.

[Anesthesia for organ transplant patients]

Organ transplant patients who must undergo nontransplant surgical interventions can be challenging for the anesthesiologists in charge. On the one hand, it is important to carefully monitor the graft function in the perioperative period with respect to the occurrence of a possible rejection reaction. On the other hand, the ongoing immunosuppression may have to be adapted to the perioperative requirements in terms of the active substance and the route of administration, the resulting increased risk of infection and possible side effects (e.g., myelosuppression, nephrotoxicity and impairment of wound healing) must be included in the perioperative treatment concept. Furthermore, possible persistent comorbidities of the underlying disease and physiological peculiarities as a result of the organ transplantation must be taken into account. Support can be obtained from the expertise of the respective transplantation center.

Hypoalbuminemia is a risk factor for invasive fungal infections and poor outcomes in infected kidney transplant recipients

INTRODUCTION

Invasive fungal infections (IFI), are estimated to occur in 2%-14% of kidney transplant recipients (KTRs) in the current era of immune suppression and are associated with high mortality rates. We hypothesized that hypoalbuminemia in KTRs is a risk factor for IFI and would be associated with poor outcomes.

METHODS

In this study, using data from a prospective cohort registry, we describe the frequency of IFI due to Blastomycosis, Coccidioidomycosis, Histoplasmosis, Aspergillosis, and Cryptococcus in KTRs with serum albumin levels measured 3-6 months before diagnosis. Controls were selected based on incidence density sampling. KTRs were divided into three groups based on the pre-IFI serum albumin level: normal (≥4 g/dL), mild (3-4 g/dL), or severe (<3 g/dL) hypoalbuminemia. Outcomes of interest were uncensored graft failure after IFI and overall mortality.

RESULTS

A total of 113 KTRs with IFI were compared with 348 controls. The incidence rate of IFI among individuals with normal, mild, and severe hypoalbuminemia was 3.6, 8.7, and 29.3 per 100 person-years, respectively. After adjustment for multiple variables, the trend for risk of uncensored graft failure following IFI was greater in KTRS with mild (HR = 2.1; 95% CI, .75-6.1) and severe (HR = 4.47; 95% CI, 1.56-12.8) hypoalbuminemia (P-trend < .001) compared to those with normal serum albumin. Similarly, mortality was higher in severe hypoalbuminemia (HR = 1.9; 95% CI, .67-5.6) compared to normal serum albumin (P-trend < .001).

CONCLUSION

Hypoalbuminemia precedes the diagnosis of IFI in KTRs, and is associated with poor outcomes following IFI. Hypoalbuminemia may be a useful predictor of IFI in KTRs and could be incorporated into screening algorithms.

Immunological Nuances and Complications of Pediatric Organ Transplant: A Narrative Review

Organ transplantation is considered an exaggerated immune state in which the body reacts in an elaborate cascade of reactions against the lifesaving graft transplanted. Unrepairable organ damage is the main indication for a pediatric patient to undergo a transplant. The host and the donor must fulfill the criteria for a successful transplant to have as few side effects as possible. There has been much-needed research in the domain of surgery of organ transplantation, thereby extending into the pediatric age group. This article elaborates on the post-transplant management, the immuno-biochemistry aspect, and its post-surgery treatment. The post-surgery period requires great emphasis as morbidity and mortality are highest. There is much to understand about managing transplant patients to avoid complications such as infections, hypertension, or side effects of immunosuppressive drugs. The treating clinician faces the challenges of managing the dose and frequency of immuno-suppressive medicines to prevent complications in the patients. If the dose is inadequate, there are chances of graft rejection. If the immuno-suppression is prolonged, there may be chances of infections in the patient. This article aims to summarize the mechanism of graft rejection and put forth the need for further research about creating a universal protocol for managing a patient's immune system post-transplant. The authors hope this protocol will help the clinician better understand the patient's current state and help in appropriately using immuno-suppressive drugs. It calls upon the need for a reliable and easily repeatable battery of investigations that will help solve this dilemma.

Diagnosis, Prevention, and Treatment of Infections in Kidney Transplantation

Kidney transplant often is complicated by infections in the recipient from therapy-related and patient-related risk factors. Infections in kidney transplant recipients are associated with increased morbidity, mortality, and allograft dysfunction. There is a predictable timeline after kidney transplant regarding the types of pathogens causing infections, reflecting the net state of immunosuppression. In the early post-transplant period, bacterial infections comprise two thirds of all infections, followed by viral and fungal infections. Infections occurring early after kidney transplantation are generally the result of postoperative complications. In most cases, opportunistic infections occur within 6 months after kidney transplantation. They may be caused by a new infection, a donor-derived infection, or reactivation of a latent infection. Community-acquired pneumonia, upper respiratory tract infections, urinary tract infections, and gastrointestinal infections are the most common infections in the late period after transplantation when the net immunosuppression is minimal. It is crucial to seek information on the time after transplant, reflecting the net state of immunosuppression, previous history of exposure/infections, geography, and seasonal outbreaks. It is imperative that we develop regionally specific guidelines on screening, prevention, and management of infections after kidney transplantation.

Malignancy risk in kidney transplant recipients exposed to immunosuppression pre-transplant for the treatment of glomerulonephritis

BACKGROUND

Kidney transplant patients with glomerulonephritis (GN) as their native disease may receive significant amounts of pre-transplant immunosuppression (PTI), which could increase the risk for development of malignancy post-transplant.

METHODS

We conducted a single-center, retrospective study of kidney transplant recipients from January 2005 until May 2020. Patients with GN as their native kidney disease who received PTI for treatment of GN (n = 184) were compared with a control cohort (n = 579) of non-diabetic, non-PTI-receiving kidney transplant patients. We calculated hazard ratios (HR) with 95% confidence intervals (95% CI) for outcomes of first occurrence of solid or hematologic malignancy, non-melanoma skin cancer (NMSC) and post-transplant lymphoproliferative disorder (PTLD).

RESULTS

Over a median follow-up of 5.7 years, PTI for GN was associated with significantly increased risk for malignancy compared with controls [13.0%  vs 9.7%, respectively; adjusted HR 1.82 (95% CI 1.10-3.00)], but not for NMSC [10.3% vs 11.4%, respectively; adjusted HR 1.09 (95% CI 0.64-1.83)] or PTLD [3.3% vs 3.1%, respectively; adjusted HR 1.02 (95% CI 0.40-2.61)]. The risk for malignancy was significantly increased in those who received cyclophosphamide [HR 2.59 (95% CI 1.48-4.55)] or rituximab [HR 3.82 (95% CI 1.69-8.65)] pre-transplant, and particularly in those who received both cyclophosphamide and rituximab, but not for calcineurin inhibitors or mycophenolate.

CONCLUSION

The use of PTI for treatment of GN, especially cyclophosphamide or even with rituximab, is associated with increased risk for development of solid or hematologic malignancy post-transplant. These data highlight potential risks with treatment of GN and underscore the importance of post-transplant malignancy surveillance in this patient population.

COVID-19 and renal involvement: a prospective cohort study assessing the impact of mild SARS-CoV-2 infection on the kidney function of young healthy males

PURPOSE

COVID-19 frequently affects the kidneys with symptoms ranging from mild proteinuria to progressive acute kidney injury. This prospective study aimed to assess the short- and long-term impact of asymptomatic and mild COVID-19 on the renal function of healthy young adults, and to determine the correlation between viral load and kidney function among these patients.

METHODS

This was a prospective cohort study conducted over a period of 6 months. Patients were followed-up at baseline, and then after 3 and 6 months, respectively. Real-time PCR cycle threshold (CT) was used to determine the viral load and disease activity. Patients were classified into two groups with either asymptomatic COVID-19 or mild pneumonia. The assessment parameters were variables that could directly or indirectly relate to the renal function.

RESULTS

A total of 48 patients were included and evaluated. The majority of patients (62.5%) had asymptomatic COVID-19 disease. Patients with mild pneumonia had significantly higher serum creatinine (SCr) at the time of COVID-19 diagnosis (beta = 12.836, 95% CI = 2.405-23.268, P = 0.019), after 3 months (beta = 14.345, 95% CI = 1.149-27.542, P = 0.035), and after 6 months (beta = 14.100, 95% CI = 0.730-27.470, P = 0.040) compared to asymptomatic patients. Mild pneumonia was also significantly associated with lower serum albumin level at the time of COVID-19 diagnosis (beta = - 6.317, 95% CI = - 9.448-- 3.185, P < 0.001).

CONCLUSION

Mild COVID-19 is associated with mild renal involvement without AKI. Changes in the renal function appear to be related to reduced creatinine clearance and possible albumin leakage in the acute phase of the disease. The reduction in creatinine clearance is not predicted by viral load, and it appears to be a long-term effect of the disease that can last for at least 6 months.

SARS-CoV-2 versus other minor viral infection on kidney injury in asymptomatic and mildly symptomatic patients

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has become a global pandemic since December 2019. Most of the patients are mild or asymptomatic and recovered well as those suffered from other respiratory viruses. SARS-CoV-2 infection is supposed to demonstrate more sequelae. Acute kidney injury (AKI) is common among COVID-19 patients and is associated with disease severity and outcomes. Only a few studies focused on a detailed analysis of kidney damage in asymptomatic or mildly symptomatic COVID-19 patients. Whether any minor viral infection is likely to exhibit similar minor effect on renal function as COVID-19 is still unclear, and the definite pathophysiology of viral invasion is not fully understood. Currently, the proposed mechanisms of AKI include direct effects of virus on kidney, dysregulated immune response, or as a result of multi-organs failure have been proposed. This study will discuss the difference between COVID-19 and other viruses, focusing on proposed mechanisms, biomarkers and whether it matters with clinical significance.

Multimodality imaging findings of infection-induced tumors

Several infections can predispose to certain malignancies in different body parts. These infections include viral, bacterial, and fungal pathogens. Imaging plays a vital role in the diagnosis, staging, and management of these neoplastic conditions. Furthermore, it can help in differentiating infection-related non-neoplastic processes that can mimic malignancies. Both radiologists and clinicians should be familiar with these conditions. This review discusses the epidemiology, pathogenesis, and imaging features of infection-related tumors.

Perivascular Mesenchymal Stem/Stromal Cells, an Immune Privileged Niche for Viruses?

Mesenchymal stem cells (MSCs) play a critical role in response to stress such as infection. They initiate the removal of cell debris, exert major immunoregulatory activities, control pathogens, and lead to a remodeling/scarring phase. Thus, host-derived ‘danger’ factors released from damaged/infected cells (called alarmins, e.g., HMGB1, ATP, DNA) as well as pathogen-associated molecular patterns (LPS, single strand RNA) can activate MSCs located in the parenchyma and around vessels to upregulate the expression of growth factors and chemoattractant molecules that influence immune cell recruitment and stem cell mobilization. MSC, in an ultimate contribution to tissue repair, may also directly trans- or de-differentiate into specific cellular phenotypes such as osteoblasts, chondrocytes, lipofibroblasts, myofibroblasts, Schwann cells, and they may somehow recapitulate their neural crest embryonic origin. Failure to terminate such repair processes induces pathological scarring, termed fibrosis, or vascular calcification. Interestingly, many viruses and particularly those associated to chronic infection and inflammation may hijack and polarize MSC’s immune regulatory activities. Several reports argue that MSC may constitute immune privileged sanctuaries for viruses and contributing to long-lasting effects posing infectious challenges, such as viruses rebounding in immunocompromised patients or following regenerative medicine therapies using MSC. We will herein review the capacity of several viruses not only to infect but also to polarize directly or indirectly the functions of MSC (immunoregulation, differentiation potential, and tissue repair) in clinical settings.

IL-37 overexpression promotes endometrial regenerative cell-mediated inhibition of cardiac allograft rejection

BACKGROUND

Endometrial regenerative cells (ERCs) play an important role in attenuation of acute allograft rejection, while their effects are limited. IL-37, a newly discovered immunoregulatory cytokine of the IL-1 family, can regulate both innate and adaptive immunity. Whether IL-37 overexpression can enhance the therapeutic effects of ERCs in inhibition of acute cardiac allograft rejection remains unknown and will be explored in this study.

METHODS

C57BL/6 mice recipients receiving BALB/c mouse heterotopic heart allografts were randomly divided into the phosphate-buffered saline (untreated), ERC treated, negative lentiviral control ERC (NC-ERC) treated, and IL-37 overexpressing ERC (IL-37-ERC) treated groups. Graft pathological changes were assessed by H&E staining. The intra-graft cell infiltration and splenic immune cell populations were analyzed by immunohistochemistry and flow cytometry, respectively. The stimulatory property of recipient DCs was tested by an MLR assay. Furthermore, serum cytokine profiles of recipients were measured by ELISA assay.

RESULTS

Mice treated with IL-37-ERCs achieved significantly prolonged allograft survival compared with the ERC-treated group. Compared with all the other control groups, IL-37-ERC-treated group showed mitigated inflammatory response, a significant increase in tolerogenic dendritic cells (Tol-DCs), regulatory T cells (Tregs) in the grafts and spleens, while a reduction of Th1 and Th17 cell population. Additionally, there was a significant upregulation of immunoregulatory IL-10, while a reduction of IFN-γ, IL-17A, IL-12 was detected in the sera of IL-37-ERC-treated recipients.

CONCLUSION

IL-37 overexpression can promote the therapeutic effects of ERCs to inhibit acute allograft rejection and further prolong graft survival. This study suggests that gene-modified ERCs overexpressing IL-37 may pave the way for novel therapeutic options in the field of transplantation.

Molecular Detection and Glycoprotein B (UL55) Genotyping of Cytomegalovirus among Sudanese Renal Transplant Recipients

Background

Cytomegalovirus (CMV) is the most common opportunistic pathogen among renal transplants with significant morbidity and mortality. This study was designed to detect CMV DNA and to determine the frequency of different glycoprotein B (UL55) genotypes among Sudanese renal transplant recipients.

Methods

One hundred and four renal transplant recipients were included in this study. A blood specimen was collected from each recipient. DNA was extracted from plasma using the QIAamp DNA mini kit. CMV amplification and quantification were performed using CMV Real-RT Quant kits. Genotyping of human CMV gB was carried out by nested PCR and sequencing of the highly diverse region of gB.

Results

CMV DNA was detected in 40/104 (38.5%) of renal transplant recipients. The average of the CMV DNA viral load was 358 × 10⁴ copies/ml (6.5 log₁₀) ranging from 62 copies/ml (1.8 log₁₀) to 1.43 × 10⁸ copies/ml (9 log₁₀). CMV viremia was detected in 60% of recipients of less than 1–12 months, 17% of 13–24, 10% of 25–36, 5% of 37–48, and 8% in more than 48 months posttransplantation with no association (p = 0.296) between CMV viremia and postrenal transplantation time. The association between the type of immunosuppressive drugs and high viral loads (>1000 copies/ml) showed a significant difference (p = 0.05). The association between CMV loads of >1000 copies/ml and symptoms of CMV disease was highly significant (p ≤ 0.001). Fever 7 (41%), fever and leucopenia 6 (35%), and gastrointestinal disease 4 (24%) were the most common symptoms of CMV disease. CMV genotyping revealed 8 cases (80%) for gB3 and 2 cases (20%) for gB4 genotypes. The most frequent genotype among Sudanese renal transplant recipients was gB3.

Conclusions

The frequency of CMV DNA is high among Sudanese renal transplant recipients. CMV gB3 is the most predominant glycoprotein B genotype in Sudanese renal transplant recipients.

Feasibility and acceptability of high-intensity interval training and moderate-intensity continuous training in kidney transplant recipients: the PACE-KD study

Background

Kidney transplant recipients (KTRs) exhibit unique elevated inflammation, impaired immune function, and increased cardiovascular risk. Although exercise reduces cardiovascular risk, there is limited research on this population, particularly surrounding novel high-intensity interval training (HIIT). The purpose of this pilot study was to determine the feasibility and acceptability of HIIT in KTRs.

Methods

Twenty KTRs (male 14; eGFR 58±19 mL/min/1.73 m²; age 49±11 years) were randomised and completed one of three trials: HIIT A (4-, 2-, and 1-min intervals; 80–90% watts at V̇O_2peak), HIITB (4×4 min intervals; 80–90% V̇O_2peak) or MICT (~40 min; 50–60% V̇O_2peak) for 24 supervised sessions on a stationary bike (approx. 3x/week over 8 weeks) and followed up for 3 months. Feasibility was assessed by recruitment, retention, and intervention acceptability and adherence.

Results

Twenty participants completed the intervention, and 8 of whom achieved the required intensity based on power output (HIIT A, 0/6 [0%]; HIITB, 3/8 [38%]; MICT, 5/6 [83%]). Participants completed 92% of the 24 sessions with 105 cancelled and rescheduled sessions and an average of 10 weeks to complete the intervention. Pre-intervention versus post-intervention V̇O_2peak (mL/kg^-1/min^-1) was 24.28±4.91 versus 27.06±4.82 in HIITA, 24.65±7.67 versus 27.48±8.23 in HIIT B, and 29.33±9.04 versus 33.05±9.90 in MICT. No adverse events were reported.

Conclusions

This is the first study to report the feasibility of HIIT in KTRs. Although participants struggled to achieve the required intensity (power), this study highlights the potential that exercise has to reduce cardiovascular risk in KTRs. HIIT and MICT performed on a cycle, with some modification, could be considered safe and feasible in KTRs. Larger scale trials are required to assess the efficacy of HIIT in KTRs and in particular identify the most appropriate intensities, recovery periods, and session duration. Some flexibility in delivery, such as incorporating home-based sessions, may need to be considered to improve recruitment and retention.

Trial registration

ISRCTN, ISRCTN17122775. Registered on 30 January 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-022-01067-3.

Long-Term Infectious Complications of Kidney Transplantation

Infections remain a common complication of solid-organ transplantation. Most infections in the first month after transplant are typically health care-associated infections, whereas late infections, beyond 6-12 months, are community-acquired infections. Opportunistic infections most frequently present in the first 12 months post-transplant and can be modulated on prior exposures and use of prophylaxis. In this review, we summarize the current epidemiology of postkidney transplant infections with a focus on key viral (BK polyomavirus, cytomegalovirus, Epstein-Barr virus, and norovirus), bacterial (urinary tract infections and Clostridioides difficile colitis), and fungal infections. Current guidelines for safe living post-transplant are also summarized. Literature supporting prophylaxis and vaccination is also provided.

Cytomegalovirus infection after renal transplantation

Renal transplant patients show a high prevalence of cytomegalovirus (CMV) infection after the procedure. This study was conducted to assess the prevalence and factors associated with the incidence of CMV infection among renal transplant patients. A total of 100 patients were recruited in this study. The CMV load in the blood of each patient was assessed using the technique of polymerase chain reaction (PCR). The serostatus of all recipients and donors was examined preoperatively and those of the recipients again postoperatively. The association of CMV load was assessed with the following factors: age, gender, alanine aminotransferase (ALT) and serum creatinine levels, types of immunosuppressive and induction regimens, preoperative diabetes status, and serological virologic response (SVR) at 12 weeks postoperatively. Our findings showed that CMV incidence was significantly higher in middle-aged patients (62 of 66 patients, 93.9%; p=0.0001). Furthermore, about 88.2% of patients induced by anti-thymocyte globulin (ATG) showed a high viral load, significantly higher than the proportion of CMV-positive patients induced by basiliximab (p=0.001). In addition, a higher proportion of CMV-negative recipients who received the graft from CMV-positive donors and vice-versa were CMV-positive postoperatively. Administration of Valcyte 450 showed 100% efficiency in decreasing the CMV load in the patients. Among all the assessed factors, only the age of the recipients, type of induction therapy used, and the preoperative serostatus of both donors and recipients were significantly associated with the postoperative CMV incidence among the patients.

Incidence and mortality of post-transplant lymphoproliferative disorders after kidney transplantation: A real-world retrospective analysis in Japan

OBJECTIVES

Post-transplant lymphoproliferative disorder is a potentially life-threatening complication that has a greater risk of occurrence in the setting of immunosuppression and oncogenic viral infections after transplant surgery. Few studies have reported the cumulative incidence, histological subtypes and clinical outcomes of this disorder in kidney transplant recipients.

METHODS

We retrospectively investigated 34 post-transplant lymphoproliferative disorder patients diagnosed out of the 1210 kidney transplant recipients who had undergone the surgery at the two largest centers in Japan between January 1983 and December 2017.

RESULTS

A total of 32 patients (94.1%) developed late-onset post-transplant lymphoproliferative disorder (diagnosed 1 year after transplantation). The cumulative incidence rates were 0.76% and 1.59% at 5 and 10 years post-transplantation, respectively. The central nervous system was the most common site (35.3%, 12/34). Overall survival was similar between patients with and without central nervous system lesions (P = 0.676). Of all of the cases, 23.5% (8/34) were detected through cancer screening. Importantly, patients with screening-detected post-transplant lymphoproliferative disorder had better overall survival than those with the disorder who had been symptom detected (P = 0.0215). Overall survival was significantly reduced in patients who developed the disorder compared with those who did not (P = 0.0001).

CONCLUSIONS

Post-transplant lymphoproliferative disorder was more likely to occur in the late post-transplantation period, which showed that long-term medical examination for transplant recipients is required. Based on our findings, we propose vigilant, long-term, cancer screening in kidney transplant recipients.

Coronavirus disease 2019 and renal transplantation

Ever since the severe acute respiratory syndrome virus causing coronavirus disease 2019 (COVID-19) struck the world, global health strategies have changed significantly. According to the Centers for Disease Control and Prevention, kidney transplant recipients are stratified as being high risk of developing fatal illness from COVID-19 infection. Kidney transplant is the gold-standard treatment for end-stage kidney disease subjects. During the pandemic, significant concerns have emerged regarding continuation of kidney transplant surgeries and management of kidney transplant recipients post-transplant. The added risk of immunosuppression in this cohort was and remains a theoretical concern, posing a potential risk of transplantation rather than benefit. This comprehensive review aims to cover most of the faced challenges in kidney transplantation in different stages of the pandemic. In addition, it will elucidate the epidemiology, nature, course of the disease, surgical consideration in donors and recipients as well as role of immunosuppression and management of COVID-19 infected kidney transplant recipients during these extraordinary circumstances.

Association of IL-15 and IP-10 Serum Levels with Cytomegalovirus Infection, CMV Viral Load and Cyclosporine Level after Kidney Transplantation

BACKGROUND

Cytomegalovirus (CMV) infection is the most common complications following kidney transplantation. Natural killer (NK) cells demonstrated critical anti-viral role in controlling and elimination of CMV after transplantation. Interleukin-15 (IL-15) is a pleiotropic cytokine that promotes the activity of NK cells and strengthens the acquired immune system. Also, IP10 (CXCL10) is a chemotactic factor which regulates NK cell recruitment and antiviral immune response. We aimed to determine the correlation between the serum levels of IL-15 and IP-10 cytokines with CMV infection, CMV viral load, and cyclosporine as a major immunosuppressive treatment after transplantation.

METHODS

Fifty-eight kidney transplant recipient patients without evidence of CMV virus disease before transplantation surgery were included in the study. From the day of transplant surgery, the patients were evaluated based on the presence of CMV Ag pp65, CMV viral load, serum levels of IL-15 & IP-10, Cyclosporine levels (C0 & C2), Glomerular Filtration Rate (GFR), and hematological & biochemical Index, up to 75 days.

RESULTS

Comparison analysis of serum levels of IL-15 and IP-10 showed no significant association with CMV infection in kidney transplant recipients. In addition, CMV viral load and cyclosporine levels at C0 and C2 did not affect patients' IL-15 and IP-10 levels.

CONCLUSION

The levels of IP-10 and IL-15 cytokines are not affected with CMV infection, even if a viral infection occurs in the early days after transplantation or long afterwards. In addition, taking the different levels of cyclosporine did not affect the cytokines levels. Other mechanisms may play a role in maintaining the levels of these cytokines.

Biomarkers Linked with Dynamic Changes of Renal Function in Asymptomatic and Mildly Symptomatic COVID-19 Patients

The catastrophic coronavirus disease 2019 (COVID-19) pandemic is currently a critical global issue. One well-known complication of COVID-19 in severe cases is acute kidney injury, but no research has given a description of its impact on the kidney in patients with mild symptoms. We explore the renal function changes in mild COVID-19 patients. This retrospective, single-center study included 27 participants with laboratory-detected severe acute respiratory syndrome coronavirus two (SARS-CoV-2) infection who were admitted to the Tri-Service General Hospital from 4 February to 26 May 2020 and analyzed their clinical features, radiological findings, and laboratory data. Data collected upon admission and discharge showed a median estimated glomerular filtration rate (eGFR) of 106.7 mL/min/1.732 m² and 112.2 mL/min/1.732 m², respectively, with a p-value of 0.044. A correlation between renal function and the severity of infection was also found and was statistically significant upon admission. Patients with a lower lymphocyte count or higher C-reactive protein, neutrophil count, and neutrophil-to-lymphocyte ratio presented with a decreased eGFR during their early infection phase. The biomarkers (CRP and NLR) may be linked with dynamic changes of renal function in COVID-19 patients who are asymptomatic or have mild symptoms.

Risk Factors and Management of Leukopenia After Kidney Transplantation: A Single-Center Experience

BACKGROUND

Leukopenia is a common complication after kidney transplantation. The etiology is multifactorial, with medication adverse effects and cytomegalovirus infection as main causes. Optimal strategies to prevent or treat posttransplant leukopenia remain unknown. We aimed to identify risk factors for leukopenia and to investigate the benefit of switching the immunosuppressive therapy to hydrocortisone as a continuous infusion.

METHODS

We retrospectively evaluated all patients with leukopenia after kidney transplantation between 2007 and 2017 at our center relative to age- and sex-matched controls.

RESULTS

Leukopenia was associated with the degree of rejection therapy before leukopenia, the immunosuppressive therapy before transplantation, and an induction therapy with rabbit antithymocyte globulin. Patients with leukopenia exhibited increased mortality, an increased incidence of bacterial and viral infections, and more acute rejections. Switching to hydrocortisone as a continuous infusion in patients with severe leukopenia decreased the duration of leukopenia and the incidence of subsequent viral infections, especially with cytomegalovirus.

CONCLUSION

Leukopenia is a risk factor for infectious complications and mortality, and it is associated with acute rejection. Switching immunosuppressive therapy to hydrocortisone as a continuous infusion is a safe approach to reduce the duration of leukopenia and the incidence of viral infections.

Role of Virus-Specific T Cell Therapy for Cytomegalovirus and BK Infections in Kidney Transplant Recipients

Cytomegalovirus (CMV) and BK virus (BKV) are common viral infections after kidney transplant. Their negative effects on patient and graft outcomes have been well described. However, despite improvement in screening and prophylaxis strategies, CMV and BKV continue to negatively affect both short- and long-term graft survival. Adequate cell-mediated immunity is essential for the control and prevention of opportunistic viral infections, such as CMV and BKV. Therefore, immune reconstitution, in particular T cell recovery, is a key factor in antiviral control after kidney transplantation. Cell-based immunotherapy offers an attractive alternative approach to traditional interventions. Adoptive T cell transfer, via infusions of allogeneic virus-specific T lymphocytes is capable of restoring virus-specific T cell immunity, and are safe and effective in the treatment of viral infections after hematopoietic stem cell transplantation. In this article, we review the emerging role of virus-specific T cell therapy in the management of CMV and BKV after kidney transplantation. On the basis of the available data, virus-specific T cell therapy may be a promising addition to the antiviral treatment armamentarium after kidney transplantation. Future studies are needed to more clearly define the efficacy and risks of virus-specific T cell therapy in the kidney transplant population.

Mesenchymal Stromal Cell Therapy in Solid Organ Transplantation

Transplantation is the gold-standard treatment for the failure of several solid organs, including the kidneys, liver, heart, lung and small bowel. The use of tailored immunosuppressive agents has improved graft and patient survival remarkably in early post-transplant stages, but long-term outcomes are frequently unsatisfactory due to the development of chronic graft rejection, which ultimately leads to transplant failure. Moreover, prolonged immunosuppression entails severe side effects that severely impact patient survival and quality of life. The achievement of tolerance, i.e., stable graft function without the need for immunosuppression, is considered the Holy Grail of the field of solid organ transplantation. However, spontaneous tolerance in solid allograft recipients is a rare and unpredictable event. Several strategies that include peri-transplant administration of non-hematopoietic immunomodulatory cells can safely and effectively induce tolerance in pre-clinical models of solid organ transplantation. Mesenchymal stromal cells (MSC), non-hematopoietic cells that can be obtained from several adult and fetal tissues, are among the most promising candidates. In this review, we will focus on current pre-clinical evidence of the immunomodulatory effect of MSC in solid organ transplantation, and discuss the available evidence of their safety and efficacy in clinical trials.

The risk factor analysis and treatment experience in pneumocystis jirovecii pneumonia after kidney transplantation

BACKGROUND

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection among solid organ transplantation. The occurrence of PJP is dangerous and fatal if there is no early identification and sufficient treatment.

OBJECTIVE

The aim of this study was to evaluate the risk factors and provide appropriate strategies of prophylaxis and treatment for PJP after kidney transplantation in our centre.

PATIENTS/METHODS

From January 2009 to December 2018, a total of 167 kidney transplantation recipients with pneumonia were enrolled, including 47 PJP patients as PJP group and 120 non-PJP patients as control group. The clinical characteristics of the two groups were analysed retrospectively.

RESULTS

Multivariate analysis showed that high total dosage of ATG [OR, 2.03; 95% CI, 1.12-3.68] and cytomegalovirus (CMV) infection were independent risk factors for PJP. Trimethoprim-sulfamethoxazole (TMP-SMX) (1.44 g q6h)-based treatment was used for 2 weeks, and its dosage and course were adjusted according to the therapeutic effect and side effects. Forty-five cases were recovered after 3 months of follow-up, and two patients died of respiratory failure. TMP-SMX (0.48 g/day) prophylaxis was used for 3-6 months and prolonged to 7-8 months after treatment for acute rejection, which reduced the incidence of PJP compared with those without prophylaxis.

CONCLUSION

Our study suggests that the high total dosage of ATG and CMV infection indicate the increased risk of PJP. The strategies of prophylaxis and treatment for PJP after kidney transplantation in our centre were effective.

Establishing best practices in measles, mumps, and rubella serologic screening for kidney transplant candidates

Optimizing immunity against vaccine-preventable diseases improves outcomes in kidney transplant (KT) patients (Arora et al, World J Transplant, 2019, 9:1; Sester et al, Transplant Rev, 2008, 22:274; Fishman, N Engl J Med, 2007, 357:2601). The American Society for Transplantation (AST) Clinical Practice Guidelines advises that serologic screening for measles, mumps, and rubella (MMR) be conducted for all KT candidates, since live-attenuated vaccines are contraindicated post-transplantation (Malinis et al, Clin Transplant, 2019, 33:e13548). Our team at Mayo Clinic Florida (MCF) conducted a quality improvement (QI) initiative to establish a best MMR screening and immunizations clinical practice in KT candidates using a Plan-Do-Study-Act (PDSA) model. By retrospective chart review of all KT candidates evaluated at our institution from January 1, 2016 to December 31, 2017, baseline data determining the rate of MMR serologic screening was established. PDSA cycles were implemented to adopt protocol-driven testing for MMR serologies, immunization documentation, and vaccination in cases of seronegativity to any of the three MMR viruses in all pre-KT candidates. Two PDSA cycles were completed in 4 months. The study population totaled 447 patients (baseline n = 283, PDSA 1 n = 61, PDSA 2 n = 103). Baseline data showed that 83% (n = 235) of pre-KT candidates received infectious disease consultation (IDC). Complete MMR (all three viruses) serological screening in KT candidates improved from baseline 3.9%-87.4% post-PDSA cycle 2 (P < .001). Necessary immunizations per AST guidelines were ordered in only 41.1% (n = 23) of the control cohort vs 100% (n = 12) and 96.9% (n = 31) of PDSA cycles 1 and 2, respectively (P < .001). The data reflect significant practice improvements in MMR screening and immunization rates among KT candidates by using protocol-driven orders combined with our pre-existing IDCs.

Viral Genomic Characterization and Replication Pattern of Human Polyomaviruses in Kidney Transplant Recipients

Human Polyomavirus (HPyV) infections are common, ranging from 60% to 100%. In kidney transplant (KTx) recipients, HPyVs have been associated with allograft nephropathy, progressive multifocal leukoencephalopathy, and skin cancer. Whether such complications are caused by viral reactivation or primary infection transmitted by the donor remains debated. This study aimed to investigate the replication pattern and genomic characterization of BK Polyomavirus (BKPyV), JC Polyomavirus (JCPyV), and Merkel Cell Polyomavirus (MCPyV) infections in KTx. Urine samples from 57 KTx donor/recipient pairs were collected immediately before organ retrieval/transplant and periodically up to post-operative day 540. Specimens were tested for the presence of BKPyV, JCPyV, and MCPyV genome by virus-specific Real-Time PCR and molecularly characterized. HPyVs genome was detected in 49.1% of donors and 77.2% of recipients. Sequences analysis revealed the archetypal strain for JCPyV, TU and Dunlop strains for BKPyV, and IIa-2 strain for MCPyV. VP1 genotyping showed a high frequency for JCPyV genotype 1 and BKPyV genotype I. Our experience demonstrates that after KTx, HPyVs genome remains stable over time with no emergence of quasi-species. HPyVs strains isolated in donor/recipient pairs are mostly identical, suggesting that viruses detected in the recipient may be transmitted by the allograft.

Kinetics of cytomegalovirus and Epstein-Barr virus DNA in whole blood and plasma of kidney transplant recipients: Implications on management strategies

This retrospective multicenter cohort study investigated the kinetics (ascending and descending phases) of cytomegalovirus (CMV) and Epstein-Barr virus (EBV)-DNA in whole blood (WB) and plasma samples collected from adult kidney transplant (KT) recipients. CMV-DNA kinetics according to antiviral therapy were investigated. Three hundred twenty-eight paired samples from 42 episodes of CMV infection and 157 paired samples from 26 episodes of EBV infection were analyzed by a single commercial molecular method approved by regulatory agencies for both matrices. CMV-DNAemia followed different kinetics in WB and plasma. In the descending phase of infection, a slower decay of viral load and a higher percentage of CMV-DNA positive samples were observed in plasma versus WB. In the 72.4% of patients receiving antiviral therapy, monitoring with plasma CMV-DNAemia versus WB CMV-DNAemia could delay treatment interruption by 7–14 days. Discontinuation of therapy based on WB monitoring did not result in relapsed infection in any patients. Highly different EBV-DNA kinetics in WB and plasma were observed due to lower positivity in plasma; EBV positive samples with a quantitative result in both blood compartments were observed in only 11.5% of cases. Our results emphasize the potential role of WB as specimen type for post-KT surveillance of both infections for disease prevention and management.

Coinfection rates and clinical outcome data for cytomegalovirus and Epstein-Barr virus in post-transplant patients: A systematic review of the literature

Background

In transplant recipients, cytomegalovirus (CMV) infection increases morbidity and mortality; furthermore, coinfection with other human herpesviruses like the Epstein‐Barr virus (EBV) may complicate their management. This systematic literature review aimed to summarize rates of CMV‐EBV coinfection and associated clinical outcomes among solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients.

Methods

An electronic literature search was performed using pre‐specified search strategies (January 1, 2010‐October 31, 2018) and following established/best practice methodology. Of 316 publications identified, 294 did not report CMV‐EBV coinfection and were excluded. Studies meeting the inclusion criteria were further analyzed. Due to limited reporting/heterogeneity, data were not meta‐analyzable.

Results

Nine studies (six SOT; three HSCT) reported CMV‐EBV coinfection; rates of coinfection post transplantation varied between 2.6% and 32.7%. Two studies indicated CMV reactivation to be an independent variable associated with EBV reactivation. Among SOT studies, higher rates of graft dysfunction (47.4% vs 22.9%), rejection episodes (20.0% vs 8.9%), or acute rejection (50.0% vs 31.0%) were reported for patients with coinfection than without. In HSCT studies, patients with graft‐vs‐host disease were not reported separately for coinfection. Two studies described cases of post‐transplant lymphoproliferative disorder (PTLD) in patients with CMV‐EBV coinfection and reported rates of PTLD of 92% and 100%.

Conclusion

The CMV‐EBV coinfection rate in HSCT and SOT recipients varied and was associated with increased graft rejection and PTLD compared with patients without coinfection. Further research may improve understanding of the burden of CMV‐EBV coinfection among transplant recipients.

The impact of the COVID-19 pandemic on renal transplantation in the UK

COVID-19 is impacting provision of renal transplantation in the UK with a reduction in clinical activity. Publicly available Renal Registry and NHS Blood and Transplant reports were analysed to model the number of missed transplant opportunities, waiting list size and change in dialysis population over a six-month period starting 5 March 2020. An estimated 1,670 kidney transplant opportunities may be lost, which will lead to 6,317 active patients on the kidney-alone waiting list, compared to 4,649 based on usual activity estimates. This will result in 1,324 additional patients on dialysis who would otherwise have been transplanted. COVID-19 will lead to a marked loss of transplant opportunities and a significantly larger national waiting list. The existing strain on dialysis capacity will be exacerbated as patients remain on dialysis as the only available form of renal replacement therapy. These findings will help inform policy and service specific strategies.

Relationship between rabbit anti-thymocyte globulin and development of PTLD and its aggressive form in renal transplant population

Introduction

The aim of our study is to explore the relationship of rabbit anti-thymocyte globulin (R-ATG) on development of post-transplant lymphoproliferative disease (PTLD) and its aggressive forms (monomorphic PTLD and Hodgkin lymphoma) in renal transplant recipients.

Methodology

All patients diagnosed with PTLD post-renal transplant in the United States’ Organ Procurement and Transplantation Network from 2003 till 2013 and followed up till 2017 were retrospectively reviewed. Multi-variable logistic regression analysis assessed association of R-ATG to development of PTLD and its aggressive form.

Results

Risk of developing PTLD post renal transplant is 1.35%. In comparison to interleukin-2 blocker induction therapy, R-ATG is associated with increased risk of development of PTLD (Odds Ratio = 1.48, confidence interval ranges from 1.04 to 2.11, p = .02) and is associated with higher risk of development of aggressive PTLD (Odds Ratio = 1.83, confidence interval ranges from 1.001 to 3.34, p = .04).

Conclusion

We conclude that R-ATG induction is associated with a higher risk of PTLD and its aggressive form (monomorphic PTLD and Hodgkin lymphoma). Careful monitoring for development of PTLD in renal transplant recipients receiving R-ATG induction therapy is advised.

Effect of Posttransplant Diabetes Mellitus on Graft Loss After Living-Donor Kidney Transplant at a Single Institution

BACKGROUND

This study aimed to evaluate predictive factors for graft loss in patients who received kidney transplantation (KT) from living kidney donors (LKDs) at a single institute in Japan.

METHODS

Our study focused on patients with end-stage renal disease who underwent KT from LKDs and were followed up for at least 1 year after surgery. The primary end point was graft survival (GS). GS after KT was analyzed using the Kaplan-Meier method. GS according to subgroup classification was analyzed using the log-rank test. A multivariate analysis was performed using a Cox proportional hazard model.

RESULTS

The median follow-up period was 105.5 months after KT. The 5- and 10-year GS rates were 97.8% and 96.0% in KT recipients (KTRs) without posttransplant diabetes mellitus (PTDM) and 89.9% and 63.2% in those with PTDM, respectively. The rate of graft loss was significantly higher in KTRs with PTDM than in those without PTDM (P < .001). Of the KTRs whose diabetes mellitus (DM) was cured after KT, those who underwent dialysis because of diabetic nephropathy had no graft loss. In the multivariate analysis, the serum creatinine level at 1 month after KT, PTDM, and human leukocyte antigen mismatches were significantly associated with graft loss after KT.

CONCLUSIONS

In this study, the rate of graft loss in KTRs with PTDM was significantly higher than that of KTRs without PTDM. However, among KTRs whose DM was cured after KT, those who underwent dialysis because of diabetic nephropathy had no graft loss.

A retrospective study of the relationship between postoperative urine output and one year transplanted kidney function

BACKGROUND

Kidney transplantation (KT) is the most obvious method of treating a patient with end-stage renal disease. In the early stages of KT, urine production is considered a marker of successful reperfusion of the kidney after anastomosis. However, there is no clear conclusion about the relationship between initial urine output after KT and 1-year renal function. Thus, we investigated the factors that affect 1-year kidney function after KT, including urine output.

METHODS

This retrospective study investigated the relationship between urine output in the 3 days after KT and transplanted kidney prognosis after 1-year. In total, 291 patients (129 living-donor and 162 deceased-donor transplant recipients) were analyzed; 24-h urine volume per body weight (in kilograms) was measured for 3 days postoperatively. The estimated glomerular filtration rate (eGFR), determined by the Modification of Diet in Renal Disease algorithm, was used as an index of renal function. Patients were grouped according to eGFR at 1-year after KT: a good residual function group, eGFR ≥60, and a poor residual function group, eGFR < 60.

RESULT

Recipients' factors affecting 1-year eGFR include height (P = 0.03), weight (P = 0.00), and body mass index (P = 0.00). Donor factors affecting 1-year eGFR include age (P = 0.00) and number of human leukocyte antigen (HLA) mismatches (P = 0.00). The urine output for 3 days after KT (postoperative day 1; 2 and 3) was associated with 1-year eGFR in deceased-donor (P = 0.00; P = 0.00 and P = 0.01). And, postoperative urine output was associated with the occurrence of delayed graft function (area under curve (AUC) = 0.913; AUC = 0.984 and AUC = 0.944).

CONCLUSION

Although postoperative urine output alone is not enough to predict 1-year GFR, the incidence of delayed graft function can be predicted. Also, the appropriate urine output after KT may differ depending on the type of the transplanted kidney.

TRIAL REGISTRATION

Clinical Research Information Service of the Korea National Institute of Health in the Republic of Korea (KCT0003571).

Persistent primary cytomegalovirus infection in a kidney transplant recipient: Multi-drug resistant and compartmentalized infection leading to graft loss

Cytomegalovirus (CMV) is one of the most common opportunistic infections after transplantation. To prevent CMV infections, universal prophylaxis and pre-emptive therapy with ganciclovir or its prodrug valganciclovir is applied. However, prolonged antiviral therapy may result in drug-resistance emergence. We describe a case of a 43-year-old CMV-seronegative patient who underwent kidney transplantation from a CMV-seropositive donor and developed CMV disease despite valganciclovir prophylaxis. CMV viral load increased even though valgangiclovir dose was augmented and immunosuppressive therapy reduced. CMV genotyping revealed mutations in the viral UL97 protein kinase, explaining ganciclovir-resistant CMV infection. The viral load failed to respond to foscavir, cidofovir and CMV-neutralizing immunoglobulins. Kidney allograft dysfunction developed 3 months post-transplantation with a histopathologic diagnosis of CMV nephropathy and potentially concomitant T-cell mediated rejection. A transplantectomy was performed on day 164 post-transplantation since the patient had uncontrollable CMV disease associated with a circulating multidrug-resistant DNA polymerase-mutant virus. Detailed monitoring in this patient demonstrated hallmarks of complicated CMV disease: (i) relatively rapid evolution of drug-resistant CMV mutants in the setting of persistent high blood viral loads, (ii) emergence of viral drug-resistance linked to acute graft rejection, (iii) transient and, thereafter, lack of response to various anti-CMV treatments, (iv) compartmentalization and heterogeneity of CMV viral populations, (v) possible differential ability of viral mutants to cause disease in the graft, and (vi) detection of minor viral variants by next generation sequencing. Translational research platforms that provide rapid molecular genotyping for detection of CMV drug-resistance are essential in guiding CMV disease management in high-risk transplant recipients.

Temporal virus serological profiling of kidney graft recipients using VirScan

At this time, pretransplant viral screening of donors and recipients is based on serological status and limited to certain viruses. After transplantation, patient follow-up is based on a monitoring strategy using ELISA or PCR. Such approaches exclude other emerging viruses that can affect the transplant outcome. Recently, a multiplex unbiased array, VirScan, was developed. This tool allows the detection of antibodies against viruses, using a synthetic human virome, with minimal serum and cost. We decided to test the value of VirScan in the follow-up of a cohort of transplant recipients. We enrolled 45 kidney transplant recipients and performed virus serological profiling at day 0 and day +365, using VirScan. We compared the results obtained with ELISA/PCR assays. We detected antibody responses to 39 of the 206 species of virus present in the VirScan library, with an average of 12 species of virus per sample. VirScan gave similar results to PCR/ELISA screening tests. Using VirScan, we found that anti-viral antibody responses were largely conserved in patients during the first year after transplantation, regardless of immunosuppressive treatment. Our study suggests VirScan offers an unprecedented opportunity to screen and monitor posttransplant virus infection in a cost-effective, easy, and unbiased manner.

Human Vascular Pericytes and Cytomegalovirus Pathobiology

Pericytes are multipotent cells of the vascular system with cytoplasmic extensions proximal to endothelial cells that occur along the abluminal surface of the endothelium. The interactions between endothelial cells and pericytes are essential for proper microvascular formation, development, stabilization, and maintenance. Pericytes are essential for the regulation of paracellular flow between cells, transendothelial fluid transport, angiogenesis, and vascular immunosurveillance. They also influence the chemical composition of the surrounding microenvironment to protect endothelial cells from potential harm. Dysregulation or loss of pericyte function can result in microvascular instability and pathological consequences. Human pericytes have been shown to be targets for human cytomegalovirus (HCMV) infection and lytic replication that likely contribute to vascular inflammation. This review focuses on human vascular pericytes and their permissiveness for HCMV infection. It also discusses their implication in pathogenesis in the blood⁻brain barrier (BBB), the inner blood⁻retinal barrier (IBRB), the placenta⁻blood barrier, and the renal glomerulus as well as their potential role in subclinical vascular disease.

Optimal Use of Ganciclovir and Valganciclovir in Transplanted Patients: How Does It Relate to the Outcome?

Objective

Organ transplant recipients receive immunosuppressive regimens to prevent transplant rejection, which put them at increased risk for opportunistic infections like cytomegalovirus (CMV). Ganciclovir and Valganciclovir are mostly used to prevent or treat CMV. Any incorrect use of the drug may have serious consequences for patients. In this study, the outcome of transplant recipients was assessed in relation to the optimal or suboptimal use of Ganciclovir or Valganciclovir.

Methods

This study was performed on 148 hospitalized patients who received Ganciclovir or Valganciclovir in the nephrology and kidney transplantation departments of our university hospitals, from March 2012 to December 2016. Patients' demographic and clinical data including dose and duration of treatment were collected and then analyzed in comparison with the standard CMV treatment protocols.

Findings

About 94.6% of patients received Ganciclovir or Valganciclovir therapy consistent with the standard defined indications. The mean ratio of prescribed daily dose to the optimal dose was 2.9 in the first dose, 2.0 in the second dose, 1.3 in the third dose, and 1.5 in the fourth dose. From 148 included patients, 26.5% experienced CMV infection once, 7.2% experienced CMV infection twice, and 1.2% had CMV infection for 3 times, within six-month follow-up after first episode of antiviral therapy during hospitalization.

Conclusion

In this study, empiric anti-CMV therapy was initially given. The doses used were generally higher than recommended but we could not find more adverse events in the patients receiving high initial doses. In any case, it seems necessary to advocate use of standard treatment guidelines to avoid adverse outcomes.

Evaluation of a new extraction platform in combination with molecular assays useful for monitoring immunosuppressed patients

BACKGROUND

In the immunosuppressed, detection of viral reactivation at the earliest convenience and molecular monitoring are of paramount importance. Nucleic acid extraction has a major impact on the reliability of results obtained from molecular assays.

OBJECTIVES

The aim of this study was to investigate the accuracy of the new EMAG^® nucleic acid extraction platform and to compare the performance of the new platform to that of the standard NucliSENS^® easyMAG^® instrument in the routine clinical laboratory.

STUDY DESIGN

For accuracy testing, reference material and for comparison studies, clinical specimens were used. In addition, a lab-flow analysis including estimation of hands-on time and that for automated extraction was performed.

RESULTS

When accuracy was tested, all 89 results obtained were found to be concordant with the results expected. When 648 clinical results were compared, 85.7% were found to be within ±0.5 log₁₀ unit, 9.5% between ±0.5 and ±1.0 log₁₀ unit, and 4.8% more than ±1.0 log₁₀ unit. The overall time required for nucleic acid extraction of 8 samples in parallel was 94 min for the fully automated extraction mode and 82 min for the partly automated mode with the new platform, and 73 min with the standard instrument. Hands-on time was found to be shorter with the new platform.

CONCLUSIONS

The extraction performance of both platforms was found to be similar for EDTA whole blood, BAL, and urine specimens. The total turn-around time for nucleic acid extraction was found to be longer with the EMAG^® platform, whereas hands-on time was reduced.

A high level of urinary retinol-binding protein is associated with cytomegalovirus infection in kidney transplantation

The indirect effects of cytomegalovirus (CMV) viremia can be related to chronic changes in renal allograft structure, but its real impact in early and late graft function remains speculative. A total of 159 patients undergoing renal transplantation using a preemptive therapeutic strategy to prevent CMV disease were included in the present study. The patients were prospectively followed, with serial measurements of urinary retinol-binding protein (uRBP), a marker of proximal tubule injury. uRBP levels and their dynamic performance were compared according to CMV viremia and the 5-year estimated glomerular filtration rate (eGFR), as measured with the modification of diet in renal disease (MDRD) equation. CMV viremia was detected in 79.9% of the patients, with high uRBP levels being detected in 76.0% of these patients (compared with 40.7% in CMV-, P=0.005). High uRBP was associated with male recipients (P=0.02), the number of mismatches (P=0.02) and CMV infection (P=0.001). Five-year eGFR was worse in patients with high uRBP levels (50.3 ± 25.8 compared with 59.8 ± 26.4 ml/min, P=0.04). In a multivariate model, eGFR <60 ml/min was associated with donor age (P<0.001), the number of mismatches (P=0.04), thymoglobulin dose (P=0.02), the presence of and time with delayed graft function (DGF) (P=0.005 and P=0.04), 1-month tacrolimus levels (P=0.03), and uRBP levels after CMV treatment (P=0.01). Patients with CMV viremia in whom uRBP levels were normalized up to 3 months after treatment showed significantly better 5-year eGFR than those in whom uRBP remained high: 61.0 ± 24.2 compared with 42.3 ± 23.9 ml/min, P<0.001. CMV viremia was associated with high uRBP levels, which represent a profile of proximal tubule injury, and the dynamic performance of uRBP after treatment was associated with long-term kidney graft function.

Drug-Induced Hematological Cytopenia in Kidney Transplantation and the Challenges It Poses for Kidney Transplant Physicians

Drug-induced hematological cytopenia is common in kidney transplantation. Various cytopenia including leucopenia (neutropenia), thrombocytopenia, and anemia can occur in kidney transplant recipients. Persistent severe leucopenia or neutropenia can lead to opportunistic infections of various etiologies. On the contrary, reducing or stopping immunosuppressive medications in these events can provoke a rejection. Transplant clinicians are often faced with the delicate dilemma of balancing cytopenia and rejection from adjustments of immunosuppressive regimen. Differentials of drug-induced cytopenia are wide. Identification of culprit medication and subsequent modification is also challenging. In this review, we will discuss individual drug implicated in causing cytopenia and correlate it with corresponding literature evidence.

Mesangial cells, specialized renal pericytes and cytomegalovirus infectivity: Implications for HCMV pathology in the glomerular vascular unit and post-transplant renal disease

Background

Human Cytomegalovirus (HCMV) infection is problematic after kidney transplantation. Human mesangial cells along with human glomerular endothelial cells and podocytes constitute the renal glomerular vascular unit (GVU). HCMV infection of the GVU is poorly understood.

Methods

GVU cells infectivity was analysed by microscopy and immunofluorescence. Cytokines profiles were measured by Luminex assays. Renal tissue analysis for HCMV infection was performed by immunohistochemistry.

Results

Mesangial cells and glomerular endothelial cells but not podocytes were permissive for both lab adapted and clinical strains of HCMV. Luminex analysis of cytokines expressed by mesangial cells exposed to the SBCMV clinical strain was examined. A Tricell infection model of the GVU maintains >90% viability with a unique cytokine profile. Finally, we show αSMA stained mesangial cells permissive for HCMV in renal tissue from a transplant patient.

Conclusions

HCMV infection of mesangial cells induces angiogenic and proinflammatory cytokines that could contribute to glomerular inflammation.

Posttransplant Lymphoproliferative Disorder Presenting as Testicular Lymphoma in a Kidney Transplant Recipient: A Case Report and Review of the Literature

Posttransplant lymphoproliferative disorder (PTLD) is a malignancy caused by the immunosuppression that occurs after transplantation. It is primarily a nodal lesion but frequently it involves extranodal masses. Treatment is usually by reducing immunosuppressive therapy. Testicular lymphoma as PTLD is notably rare in documented literature and there is limited evidence of definitive treatment guidelines. This manuscript describes a patient who developed diffuse large B-cell lymphoma of his right testis one year following kidney transplantation. A diagnosis of PTLD was made and treatment with rituximab, locoregional radiotherapy, and intrathecal methotrexate in addition to the standard reduction of immunosuppression resulted in complete remission until now. We submit this case along with literature review of similar cases in the past and a review of specific peculiarities of our case with emphasis on our treatment plan to further the understanding of this diversiform disease.

High frequency of valganciclovir underdosing for cytomegalovirus prophylaxis after renal transplantation

Background

The correct valganciclovir dose for cytomegalovirus (CMV) prophylaxis depends on renal function estimated by the Cockcroft–Gault (CG) estimated creatinine clearance (CG-CrCl) formula. Patients with delayed or rapidly changing graft function after transplantation (tx) will need dose adjustments.

Methods

We performed a retrospective investigation of valganciclovir dosing in renal transplant patients receiving CMV prophylaxis between August 2003 and August 2011, and analysed valganciclovir dosing, CG-CrCl, CMV viraemia (CMV-PCR <750 copies/mL), leucopenia (<3500/µL) and neutropenia (<1500/µL) in the first year post-transplant. On Days 30 and 60 post-transplant, dosing pattern in relation to estimated creatinine clearance was analysed regarding CMV viraemia, leucopenia and neutropenia.

Results

Six hundred and thirty-five patients received valganciclovir prophylaxis that lasted 129 ± 68 days with a mean dose of 248 ± 152 mg/day of whom 112/635 (17.7%) developed CMV viraemia, 166/635 (26.1%) leucopenia and 48/635 (7.6%) neutropenia. CMV resistance within 1 year post-transplant was detected in three patients. Only 137/609 (22.6%) patients received the recommended dose, while n = 426 (70.3%) were underdosed and n = 43 (7.1%) were overdosed at Day 30 post-tx. Risk factors for CMV viraemia were donor positive D (+)/receptor negative R (−) status and short prophylaxis duration, but not low valganciclovir dose. Risk factors for developing leucopenia were D+/R− status and low renal function. No significant differences in dosing frequency were observed in patients developing neutropenia or not (P = 0.584).

Conclusion

Most patients do not receive the recommended valganciclovir dose. Despite obvious underdosing in a large proportion of patients, effective prophylaxis was maintained and it was not associated as a risk factor for CMV viraemia or leucopenia.

Infection in Kidney Transplantation

Infection is an important cause of morbidity and mortality after kidney transplantation. It has been estimated that 70% of kidney transplant recipients will experience an infection episode within the first 3 years after transplantation (Dharnidharka et al. 2007). After cardiovascular disease, infection is the second leading cause of death in recipients with allograft function (Snyder et al. 2009). The immunosuppressive therapy required to prevent organ rejection places the kidney transplant recipient at increased risk for donor-derived, nosocomial, and community-acquired infections as well as reactivation of latent pathogens. Pretransplant screening, immunizations, and optimal antibacterial and antiviral prophylaxis can help to reduce the impact of infection. Awareness of the approach to infection in the transplant recipient including diagnostic and management strategies is essential to optimizing outcomes.

Mesenchymal stromal cells for tolerance induction in organ transplantation

The primary challenge in organ transplantation continues to be the need to suppress the host immune system long-term to ensure prolonged allograft survival. Long-term non-specific immunosuppression can, however, result in life-threatening complications. Thus, efforts have been pursued to explore novel strategies that would allow minimization of maintenance immunosuppression, eventually leading to transplant tolerance. In this scenario, bone marrow-derived mesenchymal stromal cells (MSC), given their unique immunomodulatory properties to skew the balance between regulatory and memory T cells, have emerged as potential candidates for cell-based therapy to promote immune tolerance. Here, we review our initial clinical experience with bone marrow-derived MSC in living-donor kidney transplant recipients and provide an overview of the available results of other clinical programs with MSC in kidney and liver transplantation, highlighting hurdles and success of this innovative cell-based therapy.